Table 1. Amount of gas reduction and total leaf area of ten species under two gas types. Results shown below are correlation analysis between amount of SO₂, NO₂ reduction (ppm) and TLA.

Species	Gas types	Amount of Gas Reduction (ppm)	Total Leaf Area (cm2)
Cornus officinalis	NO2	0.022 ± 0.0019	589.72 ± 90.16
	SO2	0.0385 ± 0.0117	625.9 ± 54.4
Euonymus alatus	NO2	0.0415 ± 0.0022	1702.99 ± 434.54
	SO2	0.0606 ± 0.001	1121.38 ± 142.74
Ginkgo biloba	NO2	0.0154 ± 0.0038	1026.33 ± 138.22
	SO2	0.0522 ± 0.0105	1547.71 ± 442.63
Lagerstroemia indica	NO2	0.0226 ± 0.0044	712.81 ± 145.14
	SO2	0.0574 ± 0.0093	697.48 ± 81.87
Prunus × yedoensis	NO2	0.0278 ± 0.0022	899.65 ± 144.08
	SO2	0.0301 ± 0.0058	1045.52 ± 151.39
Weigela florida	NO2	0.0368 ± 0.0002	1801.41 ± 589.17
	SO2	0.0459 ± 0.0037	2791.01 ± 454.62
Zelkova serrata	NO2	0.0141 ± 0.0016	496.2 ± 84.95
	SO2	0.0427 ± 0.0075	514.67 ± 41.02
Pinus densiflora	NO2	0.0295 ± 0.0101	1598.35 ± 301.44
	SO2	0.0785 ± 0.021	6685.52 ± 856.77
Pinus strobus	NO2	0.02 ± 0.0111	6591.67 ± 397.68
	SO2	0.0553 ± 0.0121	10172.64 ± 1279.55
Pinus thunbergii	NO2	0.0374 ± 0.0005	5111.61 ± 766.66
	SO2	0.0627 ± 0.0079	3690.92 ± 1141.98
Gas types		P
NO2		0.335
SO2		0.317